An operator (called “service operator” below) providing a service to users builds an operation system in order to provide a service. In an operation system of this kind, the service operator, for example, prepares an apparatus (called “manager” below) which manages the state, etc. of resources of the operation system, and a terminal (called “operator terminal” below) which is connected to the manager via a network.
The operator terminal sends the manager an application programming interface (API) for requesting execution of a process (also called a “task” below) by the operation system. Consequently, even if the service operator has built the operation system and the manager in remotely located data centers, it is still possible to confirm the operational state of the operation system and to change settings in the hardware, etc. on which the operation system is built (see, for example, Japanese Laid-open Patent Publication No. 2004-021549, Japanese National Publication of International Patent Application No. 2007-520806 and Japanese Laid-open Patent Publication No. H07-302242).